[Severe COVID-19, a new complication to be added to numerous comorbidities associated to obesity]

Obesity is associated with a huge number of well-known comorbidities. Nowadays, it represents a higher risk of severe COVID-19 infection, which may lead to the requirement of a mechanical ventilation in intensive care units and premature death. The increase in relative risk of poor prognosis in presence of obesity is particularly high in patients at a younger age. The underlying mechanisms are multiple: alteration of the respiratory performance, presence of frequent comorbidities (diabetes, hypertension or obstructive sleep apnea), finally inadequate and excessive immunological responses, with massive liberation of cytokines (especially interkeukin-1 and interleukin-6). Thus, COVID-19 may challenge the so-called «obesity paradox» in intensive care units among patients with acute respiratory distress syndrome where obesity is commonly reported as associated with a better prognosis. In the special case of COVID-19, a condition where obviously obesity aggravates the prognosis, hypothetical mechanisms remain to be well-defined and deserve further validation.